The present disclosure relates to attaching an end of a wrapping film web to a wrapping machine when: (a) a roll of wrapping film web needs to be changed, such as when a new roll of wrapping film web needs to be installed; or (b) the wrapping film web is torn apart such that the wrapping process may continue.
Various types of wrapping machines for wrapping a web-type plastic film around an article being packaged are known. The article being packaged is typically a pallet-mounted load that usually takes the form of a rectangular parallelepiped.
In certain known wrapping machines, the plastic film web is wrapped around the load by: (a) rotating rolls of plastic film web around the pallet, (b) rotating the pallet with respect to the rolls of plastic film web, or (c) both (a) and (b) at the same time. The rolls of plastic film web are also simultaneously shifted in the vertical direction. These known wrapping machines are also typically fitted with elements configured to provide a piece of plastic film web to cover a top surface of the load to be wrapped.
During the wrapping process, the film is usually also pre-stretched to a certain degree before being wrapped around the load. The stretched film provides secure protection of the wrapped load and helps keep the wrapped products at their places on the pallet. Stretching the film also reduces the thickness of the film and, therefore, less film material is used in wrapping the load, which reduces material costs.
One way of moving rolls of film web around a stationary pallet and a load thereon is to provide the wrapping machine with a horizontally placed, ring-shaped circular guide structure that is fitted with one or more film supply carriages including a roll of film web. Such a circular guide structure can be formed, for example, from a circular guide ring mounted on a frame of the wrapping machine in a vertically movable manner and a circular guide ring that is fitted with film supply carriages and that is rotatable relative to the stationary circular guide ring. Alternatively, the circular guide structure of the wrapping machine may include only one circular guide ring that is either rotatably or non-rotatably mounted on the frame of the wrapping machine and that is also movable in the vertical direction. One known wrapping machine using circular guides is described in U.S. Pat. No. 4,587,796.
In known circular guide wrapping machines in which the wrapping film web is wrapped around a stationary load with a movable film web roll carriage, the end of the film web is generally caught in a cutting and holding device of the wrapping machine. The cutting and holding device ends the wrapping process by cutting the film web and fixing the end of the wrapped film web to the wrapped load. When a new wrapping process is started, the cutting and holding device releases the end of the film web. Generally, the cutting and holding deice does so after the first round of the film web is wrapped on the load or at another suitable time during the first wrapping rounds such that the wrapping process may continue without fear that the film web will detach itself from the load to be wrapped and the released end remains under the subsequent wrapping rounds. Thus, the wrapping machine may proceed to start wrapping a new load immediately after the new load is set in the wrapping area for wrapping without any required steps for attaching the end of the film web to the new load.
However, in cases in which: (a) a roll of wrapping film web needs to be changed, such as when a new roll of wrapping film web needs to be installed; or (b) the wrapping film web is torn apart, the free end of the film web needs to be fixed to the cutting and holding device such that the wrapping process may be started again. This reattachment process of the end of the film web to the cutting and holding device is problematic since the cutting and holding device is located in the wrapping area of the wrapping machine in which a load to be wrapped is typically present, which limits accessibility to the cutting and holding device. Additionally, the film carriage to which the roll of the wrapping film web is installed is often located in front of the cutting and holding device during the roll changing process, which further limits accessibility to the cutting and holding device. Further, the actual reattachment of the end of the film web requires use of both hands to open the required parts of the cutting and holding device and to close them again to fix the end of the film web to the cutting and holding device. Thus, the reattachment process of the end of the film web to the cutting and holding device is burdensome to a person who needs to do so.
There exists a need for new and improved methods and apparatuses for fixing the end of a wrapping film web to and releasing the end of the wrapping film web from a circular guide wrapping machine.